const s1 = Symbol('二哈')
const s2 = Symbol('二哈')
console.log(s1 == s2)
const secertKey = Symbol('secret')
console.log(secertKey)
// 多人协作中 Why Symbol ?
// 动态 不太安全？
// key string 类型 | Symbol
const a = "ecut"
const user = {
    [secertKey]: '123456',
    email: 'caobao@qq.com',
    name: '曹老板',
    "a": 456,
    [a]: 123,
}
console.log(user.ecut, user[a])
user.email = 'caobao@163.com'